This is Your Brain On Awesome Thoughts on the world from a student of the mind

28Mar/11

Nuclear power in a nutshell

With all of the media coverage going on right now about the disaster in Japan, perhaps a bit of explanation is in order. (Warning for those of you versed in the world of nuclear physics: this is going to be a relatively simple, watered-down, and incomplete idea of what goes on in a nuclear reactor...don't get mad at me!) And let me get something out of the way right from the get-go: there's not going to be a nuclear explosion in Fukushima, Japan. While atomic bombs and nuclear power plants both rely on nuclear reactions, they are extremely different when it comes to their potential to explode.

Schematic of a simple nuclear reactor like the ones in Fukushima

So here's the short version. Essentially, nuclear reactors work in the exact same way as certain other engines we've been using for hundreds of years: by using steam. At the heart of a nuclear reactor lies a chamber that is submerged in large tank of water. Inside this chamber are a number of uranium "cores," if you will. These are about the size of a Tootsie Roll, and they're totally awesome.

Why are they awesome? When the reactor is in operation, each of these cores undergoes a self-propagating nuclear reaction in which uranium atoms split apart and release massive amounts of energy. Within the chamber are millions of neutrons floating around, causing this reaction to occur. The result of all this energy is a TON of heat, and since the reactor is submerged in water, this heat creates steam that leaves the chamber and powers engines. Think of the nuclear reactor as a kind of atomic furnace, burning uranium instead of wood.

So what happens when this all breaks down? You may have noticed that I said this was a self-propagating process.  That means that you can't just stop it at will. As long as there are neutrons in the uranium chamber, nuclear fission will occur. Luckily, there are two general mechanisms to control this process. One is the water that surrounds this uranium chamber. The steam that is generated by this process is constantly being collected, cooled, and then recirculated through the system. This means that (when things are working properly), there is always a pool of water to capture the heat and keep things relatively stable.

The second control mechanism is a series of rods that can be inserted into the uranium chamber. These can be made of a number of different materials, but their key function is to "soak up" the neutrons in the chamber. As you'll recall, these neutrons are what drives the nuclear reaction, and removing them will cause this process to slow down (something you want in the event of catastrophe). If you want to slow the reactor as much as possible, you insert every rod into the core entirely and at the same time. This is called scramming the reactor, and it doesn't stop the reactor; it only slows it down.

What happened at the Fukushima plant? Believe it or not, the reactor held up to the earthquake just fine. All of the proper safety protocols were executed, and things seemed to be OK. However, safety engineers weren't prepared for a giant tsunami, and when key components of the power plant's backup electricity system were submerged in water, the reactor stopped recycling the steam that was created. As a result, two bad things happened: one was the gradual loss of the water surrounding the uranium core (since it was being turned to steam without a replacement), and the other was the increasing buildup of the steam itself.

The first is a problem because that water served as a way to carry the heat away from the uranium fuel. Without that extra cooling, the cores become so hot that they can melt. This is what is known as a "nuclear meltdown." The second (and more dangerous) problem of steam buildup arises from an interesting property of water. When steam (aka vaporized water) is heated to extremely high temperatures, it can actually cause the water molecules to break down into their component parts, hydrogen and oxygen. The important factor here is the hydrogen gas, an incredibly flammable substance that has a tendency to cause explosions. Given the super-hot temperature of the reactor, the hydrogen can explode, launching radioactive materials into the environment. In addition, if a fire is started, then smoke from the fire can carry even more radioactive particles into the air and beyond (a la Chernobyl).

We aren't sure yet what exactly happened at Fukushima, but rest assured it was not as bad as the media would have you believe. While there is a certain amount of radiation emanating from the power plant, it is far below the amount that is dangerous to humans. The situation at Fukushima could still change in a bad way, but as of now it seems that the damage has been contained. As we continue monitoring the situation in Japan, remember that this could have been a much worse catastrophe, had the proper safety mechanisms not been in place. All things considered, nuclear technology is a surprisingly safe way to get energy without carbon pollution. In the coming weeks there will be a lot of sensationalist talk about what happened at Fukushima. In light of such information, I urge you make an effort to separate fact from fiction, and as the great Douglas Adams would suggest, "Don't Panic!"

If you're still confused or curious, check out Stuff You Should Know's recent podcast on the disaster.

 

21Mar/11

Ten things you need to know about science

One of the most powerful trends of the last hundred years has been the increasing amount of "science" that exists in our classrooms.  Compared with centuries ago, our students are learning more about the empirical method and the natural world than ever before.

And yet, these fields are still held to a different standard than the old, established disciplines of literature or art or philosophy.  This is perhaps best-personified in the kinds of information that are considered to be "essential" to a well-rounded education.  It's rare to find someone who hasn't been taught the basics of Shakespeare, yet quite common to meet a college student with no idea of how basic physics works.

Perhaps one reason for this is that scientists haven't made clear what are the most important things to know.  When you look at such a diverse field, it can become difficult to figure out what facts are "essential" and which are best left to those with a strong interest.  To that extent, here is an interesting article that tries to detail the "essentials" in an attempt to provide a foundation upon which non-scientists can build their knowledge.

For those who just want a quick glimpse at what they came up with, here's the short list:

  1. Evolution
  2. Genes and DNA
  3. Big bang
  4. Relativity
  5. Quantum mechanics
  6. Radiation
  7. Atoms and nuclear reactions
  8. Molecules and chemical reactions
  9. Digital data
  10. Statistical significance

I don't agree with all of their choices on the list (not that they aren't important, I just wish they had included a basic understanding of the brain in their list, given the large number of misleading and "pop" articles on neuroscience), but it's certainly a good start.

Hopefully, the future will bring with it a culture in which it is just as shameful to be ignorant of Mendeleev as it is to be unversed in Steinbeck, where a knowledge of classics includes a knowledge of classical physics.  A well-read mind is a powerful one indeed, let's make sure we keep such an idea up-to-date.

The Financial Times article

14Mar/11

Blurring the line between man and machine

Human beings are a wonderful species, indeed. We've got the ability to think critically in difficult situations, to be flexible in the face of great adversity and challenge, and to create systems that were previously unthinkable. Our brains seem to be nature's ultimate machine, a unique network of neurons in a storm of electrical activity. This fantastic assemblage of complex components has been the sole occupant of the throne of "consciousness" (whatever that is) for thousands of years now. However, our tenure as the known universe's only sentient beings may be coming to an end.

This concept was recently discussed in an article in The Atlantic. Written by Brian Christian , a bona-fide flesh-and-blood human (honest), it covers one of the oldest questions facing humanity: what makes us special? Christian describes his experience in 2009 as a contestant in the famed "Turing test", in which computer programs attempt to fool judges into believing that they're conversing with an actual person, rather than a machine. The annual competition is a gathering place for AI enthusiasts and critics alike, where the intricacies of modern machines are pitted against the "unique" human mind. The result is an eerie battleground where the lines between silicon and carbon are blurred.

Christian's book on his encounter with the Turing test

While we are still a far cry from creating computers that are truly indistinguishable from people, the race is a heated one.  Each year brings with it a new host of artificial intelligence that is more flexible, more sophisticated, and more human than previous iterations. This allows us to dive deeper into the world of machines, better understanding their capabilities and limitations. These Turing tests also give us a refined glimpse into what it means to be a human. In fact, Christian aims for a different goal than beating out the machines: he competes for (and ultimately wins) the award of "the most human human."

What should we take from the fact that such an award even exists? Is it that technology has somehow "watered down" the pool of consciousness for some of us? Have the poignant sensations of being human become dulled after many hours in front of glowing screens and status updates? Or is it that machines are simply running a faster race than we are, zeroing in on some level of sentient perfection unhindered by the slow deliberateness of natural evolution?

Computers are becoming increasingly sophisticated, humanity's daily interaction with machines is constantly growing, and our interactions with one another seem to become defined more and more by our digital avatars rather than our flesh-and-blood selves. In such a world, it becomes difficult to predict the ramifications of advanced technology and our increasing reliance on it for work, entertainment, and sustenance. To illuminate the darkness of what it means to be human, we will have to follow the path of Brian Christian and utilize one of the most powerful and under-appreciated tools at our disposal: introspection.

 

10Mar/11

Machinery, biology, and complexity

Well unfortunately my bike is currently de-commissioned right now, and after a long and arduous attempt at fixing it myself, I've come to two realizations.  One: blindly trying to fix a bike yourself  is nearly futile and frequently a way to do even more damage to your cycle.  Two: the machines that we use every day are ridiculously, amazingly sophisticated.

The more I think about it, the more I am left in awe at the sheer diversity of mechanical devices out there.  Take the bottom bracket of my bike, for instance.  Upon approaching this problem, I assumed that fixing the ailments of my bicycle would be a simple matter of unscrewing a few bolts, maybe squeezing some oil in there, and in a worst case scenario, buying a new part.  Little did I know what I was getting myself into.

Once I got my hands dirty, I quickly realized that the gears/cranks/bottom bracket system is actually quite complex and difficult to tease apart with conventional tools.  Moreover, the bottom bracket is actually composed of numerous tiny parts itself.  Just looking at it made my brain start to pant from exhaustion.

Not what I bargained for

Luckily for us, we have the power of the internet and modern day graphics to help us visualize what some of these complex mechanical machines might be doing.  While I was unable to find a moving diagram detailing the inner workings of bikes and the bottom bracket, I did come across this gem of a page that shows simple GIFs of all kinds of mechanical systems.  Ever wonder how a sewing machine works?  How an artillery gun is loaded automatically?  How about how a manual transmission works?    Click through, and be amazed at the sheer complexity of many of the devices we take for granted each day.

One thing that I notice as I look at these animations or read about the inner workings of other devices is that I come to a new appreciation of the real value that each of these machines hold.  They make a transition from "magic box that does _____" to an interconnected system of logical parts, inspired by an astoundingly simple set of physical laws.

Then I realize that I do this every single day of my life.  It's called "science" and it entails making the same mental journey from "curiosity of the unknown" to "appreciation of complexity."  Think that a rotary engine is a complex machine?  Try looking at the nervous system of a fly.  Try understanding a single cubic inch of the human brain.

The world is an incredibly complex and beautiful place, filled with dark and twisted corridors that require deliberation and creativity to illuminate.  Whether it be in the rigid workings of a steam engine, or in the guided chaos of biological systems, complexity is a theme that you find over and over again.  Such a realization both humbles and excites me, for we aren't even close to understanding the potential that is the natural world around us.

 

2Mar/11

The Sun just tried to punch us

As we've all learned before, the sun is a terrifying beast of energy and magnetic fields that often likes to throw superheated particles, plasma, and many other anti-earth things in our direction.  Well, NASA is hard at work at imaging this gigantic beast, and they managed to capture a doosie of a video.

What you see is a 90 minute time lapse of one of the sun's famed "solar flares."  Essentially, this is what happens when a particular area on the sun undergoes a rapid change in the orientation of its magnetic fields.  As a result, an enormous amount of energy is expelled in the form of a giant arc of plasma.

These solar flares can do all kinds of strange things like mess with telecommunications and the earth's magnetic field.  The really big ones can even have strong effects on the earth's surface, such as  in 1859, when a giant coronal mass ejection resulted in several telegraph poles bursting into flames.

No one is sure what exactly causes these huge fluctuations in activity, although areas of the sun that are generally more active do tend to have a larger number of flares.  One thing is for certain though, they are fascinating, beautiful, and a force to be reckoned with.

via NASA.gov